Rescue of groundwater level time series

Rescue of groundwater level time series: How to visually identify and treat errors”

Retike, Inga (University of Latvia)
Bikše, Jānis (University of Latvia)
Kalvāns, Andis (University of Latvia)
Dēliņa, Aija (University of Latvia)
Avotniece, Zanita (University of Latvia)
Zaadnoordijk, Willem (TU Delft Water Resources; TU Delft Civil Engineering & Geosciences; TNO)
Jemeljanova, Marta (University of Latvia)
Popovs, Konrāds (University of Latvia)
Babre, Alise (University of Latvia)
Zelenkevičs, Artjoms (University of Latvia)
Baikovs, Artūrs (University of Latvia)

Civil Engineering & Geosciences

2022

Groundwater level time series are of great value for a variety of groundwater studies, particularly for those dealing with the impacts of anthropogenic and climate change. Quality control of groundwater level observations is an essential step prior to any further application, e.g., trend analysis. Often the quality control of data is limited to the removal of outliers or elimination of entire time series from a dataset, while such approaches drastically reduce the spatial coverage of initially huge datasets. Frequently studies tend to present already qualitycontrolleddata, but neglect to demonstrate how the data were selected, judged, and modified. We present a data rescue approach developed for correcting the Latvian national groundwater level database, containing 1.68 million groundwater level observations since 1959, including 0.69 million manual measurements. A web-based R-Shiny interface was developed and used for visual identification and manual correction of erroneous measurements in groundwater level time series. All data manipulations were performed programmatically. Reproducibilityand traceability were ensured by deploying separate data tables for raw observations, data repair actions and the final dataset. As a result of applied actions, 34.3% of all automatic measurements were either deleted or corrected, while only 6.5% of manual measurements were edited. Commonly found errors ingroundwater level time series were grouped into: errors in measurement and data recording; technical problems at the observation site; local anthropogenic impact and other unclassified problems. The improvement from the rescue approach was assessed by comparing the Akaike information criterion derived from fitted ARMA and ARIMA models to both original and repaired time series. The results showed that models fitted using repaired time series were better than those fitted on the original time series for the same time series sections. The presented rescue approach and results can be of great value for all studies using groundwater level time series as an input.

groundwater level
Time series
Visual Inspection
Monitoring
ARIMA models

http://resolver.tudelft.nl/uuid:69c7347f-5cbe-4fab-80f3-7e34dc54cdf5

https://doi.org/10.1016/j.jhydrol.2021.127294

0022-1694

Journal of Hydrology, 605

Original artticle excluded the Delft the affiliation (second) of Willem Jan Zaadnoordijk Corrigendum DOI 10.16/j.hydrol.2022.127563

Institutional Repository

journal article

© 2022 Inga Retike, Jānis Bikše, Andis Kalvāns, Aija Dēliņa, Zanita Avotniece, Willem Zaadnoordijk, Marta Jemeljanova, Konrāds Popovs, Alise Babre, Artjoms Zelenkevičs, Artūrs Baikovs